This is the story of a quarter-century struggle to rebuild from scrap condition a unique locomotive, it being an essential part of the British engineering heritage. It covers the unusual and efficient Caprotti valve gear in depth and solves the mystery of why the locomotive did not work properly in service. It was never improved until it was restored and its secrets revealed with a surprising conclusion.

This is the story of a quarter-century struggle to rebuild from scrap condition a unique locomotive, it being an essential part of the British engineering heritage.It covers the unusual and efficient Caprotti valve gear in depth and solves the mystery of why the locomotive did not work properly in service. It was never improved until it was restored and its secrets revealed with a surprising conclusion.